1. Field of the Invention
This invention relates to an air dryer system for use in a compressed air system. More particularly, the invention relates to an air dryer system for use in a trailer where protection that is normally provided for the tractor may not be available.
2. Discussion of the Art
Compressed air systems are widely used to operate a number of devices, and find particular use in braking systems for heavy vehicles. These systems include an air compressor which compresses ambient air and charges a storage reservoir. The compressor is engine operated and a governor, responsive to the reservoir pressure, selectively enables or disables the compressor as needed. Air dryers commonly employ a drying material or desiccant through which air passes to remove entrained moisture and limit problems associated with moisture associated with brake system components. Moisture is adsorbed by the desiccant and removed from the compressed air before it is communicated to the storage reservoir. In these known systems, periodic or cyclic purging of the air dryers is required in order to purge or regenerate the desiccant.
No provision has been made for trailer air dryers to separately protect devices that may not be protected by the tractor""s air dryer. As will be appreciated, contamination, foreign particles, leakage, and freeze-up of the pneumatic valves used in trailer braking and trailer suspension systems can be associated with the lack of an effective trailer dryer system. Therefore, there is a perceived need for a trailer air dryer that simultaneously filters and dries wet air sent to the trailer. The active drying material can act as a moisture buffer, adsorbing moisture from the air during wet air consumption, and releasing previously captured moisture in vapor phase when the incoming air is dry, thereby regenerating the desiccant in a non-cyclic fashion.
The present invention solves the noted problems and others and provides an air dryer useful in a trailer braking and suspension system.
According to the invention, an air dryer for a trailer braking assembly includes a housing having first and second passages extending therethrough. Each passage has a drying material disposed therein for removing moisture directed through the passage. A third passage provides a bypass if a predetermined differential pressure threshold is exceeded.
According to another aspect of the invention, the first and second passages are different sizes to accommodate the supply and control air, and bypasses are provided for each passage if a predetermined differential pressure threshold is exceeded.
According to another aspect of the invention, a filter is associated with the drying material in each passage to clean the air passing therethrough.
According to a still further aspect of the invention, a signal generator is associated with the housing to provide a signal to the operator that the differential pressure threshold has been exceeded.
A primary benefit of the present invention is the ability to protect devices that may or may not be protected by the tractor.
Still another benefit resides in the ease with which the air dryer assembly can be incorporated into the trailer braking system.
Yet another benefit of the invention is realized by the ability to effectively remove the air dryer from the trailer braking system if it becomes plugged or blocked.
Still other advantages and benefits of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description.